<code>linkPinning</code> - when set to <code>true</code> (the default), links can be <q>pinned</q> to the paper meaning a source or target of a link can be a point. If you do not want to let the user drag a link and drop it somewhere in a blank paper area, set this to <code>false</code>. The effect is
                              that the link will be returned to its original position whenever the user drops it somewhere in a blank paper area.
